1. Field of the Invention
The present invention relates to folding chairs and in particular relates to a folding chair that contains a safety guard to improve the structural integrity of the chair.
2. Description of the Related Art
People often use low cost folding chairs as a means for sitting in an upright position. In comparison to other seating devices, low cost folding chairs offer the advantages of being compact and lightweight. Therefore, folding chairs can be easily stored, easily transported, and supplied in great numbers at a reasonable cost.
A typical low cost folding chair consists of a seat rest, a back rest, and a plurality of foldable support structures that, when in an open position, enable the seat rest to support the weight of a person. Furthermore, the back rest helps to prevent the person from falling backwards while the person is seated in the seat rest.
The problem with many low cost folding chairs is that they sometimes lack sufficient structural integrity to support extremely heavy individuals. When a heavy individual sits in a folding chair, large internal forces are sometimes generated throughout the folding chair. It is possible for these forces to exceed the capabilities of the folding chair and result in a mechanical failure that can result in a collapse of the chair and possible injury to the person sitting in the chair.
Another problem with folding chairs is that they can sometimes inadvertently fold up while an individual is sitting in the chair. For example, if a person sitting in a folding chair attempts to pull himself forward toward a table, it is possible for the legs of the folding chair to experience forces that could cause the legs to fold together. Moreover, it is possible for the legs to approach each other to the extent that the stability of the chair could be compromised. In either circumstance, the person sitting in the chair may become unbalanced and possibly fall or, at a minimum, have to inconveniently readjust the chair.
The potential loss of mechanical stability in a folding chair poses a serious risk of injury to the user. Without a supporting structure, gravitational forces acting on an object placed at the height of 18 inches, the height of a typical seat rest, would cause the object to collide with the ground with a speed of 10 feet per second. If the ground were a solid structure such as concrete or brick, then a falling user would most likely experience extreme collision forces that could easily cause injury to the person. This problem is compounded by the likelihood that the person""s rear end will often contact the floor first risking injury to the person""s tailbone or possibly their back.
To address the forgoing concerns, folding chairs have been developed with additional structural elements. In particular, some folding chairs include a safety brace that applies inward forces on the main structural support structures when the chair is unfolded and a person is sitting in the chair. Furthermore, the brace is mounted to the chair so that it does not prevent a person from folding and unfolding the chair.
For example, some references disclose the concept of slidably mounting a first end of the brace to the chair so as to enable folding and unfolding of the chair. However, if the chair is treated roughly or if the chair is folded, stacked, transported, and unfolded many times, it is possible that the shape of the brace will become deformed. Consequently, it is likely that the sliding mechanism will not work properly, thus making it difficult or impossible to fold and unfold the chair.
From the foregoing, it will be appreciated that there is a need for a folding chair that is capable of supporting the weight of extremely heavy individuals. To this end, there is a need for a chair that is more structurally sound such that a failure of one component or piece of the chair will not necessarily result in the user falling to the ground. Furthermore, this folding chair should be lightweight, easy to use, and inexpensive to produce. Moreover, the folding chair should be able to withstand substantial abuse and repeated usage without loosing the ability to easily fold and unfold.
The aforementioned needs are satisfied by the present invention which, according to one aspect, is a folding chair having a folded and an unfolded configuration. The folding chair comprises a first support member having a first linking element and a second support member having a second linking element. The first and second chair support members are pivotally attached to each other so as to enable tilting of the first chair support member with respect to the second chair support member. The folded configuration results in (a) the first and second chair support members being substantially aligned with each other and (b) the first and second linking elements being a first distance apart. The unfolded configuration results in (a) the first and second chair support members being substantially tilted with respect to each other and (b) the first and second linking elements being a second distance from each other. The folding chair further comprises a seat that is attached to the first and second chair support members. The seat is substantially aligned with the first and second chair support members when the chair is in the folded configuration and the seat is substantially parallel to a surface upon which the first and second chair support members are positioned when the chair is in the unfolded configuration so as to enable a user to rest thereon in a seated position. The folding chair further comprises a first brace member having first and second ends. The first end of the first brace member is slidably attached to the first linking element of the first chair support member and the second end of the first brace member is slidably attached to the second linking element. The first brace member allows the distance between the first and second linking elements to vary between the first and second distances so as to enable the chair to be manipulated between the folded and unfolded configurations. The first brace member inhibits the distance between the first and second linking elements from increasing beyond the second distance so as to reduce the likelihood of the chair collapsing in response to a downward force applied on the seat when the seat is in the unfolded configuration.
In another aspect of the present invention, a folding chair is provided which comprises a first support member and a second support member pivotally attached to the first support member so as to enable the first support member to be tilted with respect to the second support member between (a) an unfolded position such that an opening angle is defined between the first and second support members and (b) a folded position such that the first and second support members are substantially aligned with each other. The folding chair further comprises a seat member coupled to the first and second support members so that the seat member is substantially aligned with the first and second support members when the first and second support members are in the folded position and so that the seat member extends between the first and second support members when the first and second support members are in the unfolded position so that the seat member is able to support the weight of an individual. The folding chair further comprises a first and second rigid safety brace member each having a first and second end. The first ends of the first and second safety brace members are slidably and rotatably attached to the first support member and the second ends of the first and second safety brace members are slidably and rotatably attached to the second support member. The first and second safety brace members inhibit the first and second support members from hyperextending beyond the open angle and the first and second safety brace members provide the first and second support members with the freedom to tilt between the unfolded position and the folded position.
In yet another aspect of the present invention, a folding chair is provided which comprises a first support member and a second support member pivotally attached to the first support member so as to enable the first support member to be tilted with respect to the second support member between (a) an unfolded configuration such that an opening angle is defined between the first and second support members and (b) a folded configuration such that the first and second support members are substantially aligned with each other. The folding chair further comprises a seat member coupled to the first and second support members such that the seat member is substantially aligned with the first and second support members when the first and second support members are in the folded configuration and such that the seat member extends between the first and second support members when the first and second support members are in the unfolded configuration so that the seat member is able to support the weight of an individual. The folding chair further comprises a brace member having a first and second end, wherein the first end of the brace member is attached to the first support member such that the first end of the brace member is movable over a first interval with respect to the first support member. Furthermore, the second end of the brace member is attached to the second support member such that the second end of the brace member is movable over a second interval with respect to the second support member. The brace member inhibits the first and second support members from hyperextending beyond the open angle. The first and second intervals are selected so that the brace member does not inhibit the first and second support members from tilting with respect to each other between the folded and unfolded configurations even if one of the first and second ends of the brace member is no longer able to move with respect to the corresponding first or second support members.
From the foregoing, it should be apparent that folding chair of the present invention contains supplementary structural elements that are sufficient to allow the chair to support the weight of extremely heavy individuals. Furthermore, the chair is capable of supporting extremely heavy individuals in the event that the seat becomes dis-attached from the chair. Moreover, the folding chair of the present invention is designed to have an extended usable lifetime with an increased likelihood that the folding chair will be usable even if the supplementary structural elements become damaged. These and other objects and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.